After you follow the steps on How to upload a PDF, you can turn on public annotations by clicking the citation 
Once you click on the citation, the more information page will slide out and you can click on the Public Annotation and toggle it On
To use social annotations, you will click View PDF on your citation
This will open the PDF in a new window
You can use the toolbar to highlight, comment, and create shapes
You can also highlight a sentence by clicking and dragging with your mouse to create comments or highlight the statement
If you wish to comment, click the speech bubble, and then the space to type comments will slide out
The comment space allows you to post private and public comments. The public comments will be seen by everyone who has access to the reading list (students and instructors) and it will allow them to reply to your comment.
Once you click Public and Save, students and instructors can reply to your comment
You can edit comments that you made by clicking the three dots (options menu) in your comment box. You can edit or delete your comment. If no one has replied yet, you can switch the comment to private.
